Blood Analysis

antagens

defense mechanisms for red blood cells; used to identify different blood types

Rhesus Factor

what labels the blood type positive or negative?

ABO

The basic classification system for blood types based on reaction of antigens and antibodies

More than 100

How many factors are in blood?

No two people except identical twins

What type of people have the same blood factors?

Serology

the study of bodily fluids

about 1/12

How much of our body is made up of blood?

RBC, WBC, and Plasma

what does the blood contain?

Plasma

This is the fluid portion of blood; makes up 55% of total composition of blood

90% water and 10% metabolites and waste

what is plasma composed of

Erythocytes

whats another word for red blood cells?

hemobglobin

red blood cells get their color from where?

transport oxygen from the lungs to the other cells in the body

what is the main function of the RBC

Leukoeytes

what is another word for white blood cells?

primary cells that make up the immune system.

what is the main function of leukoeytes?

platelets

anucleated broken up pieces of cells that start the clotting process; they initiate the formation of fibrin used to form a clot

hemoglobin

the oxygen carrying substance in blood cells that breaks down peroxides with the production of oxygen

oxygen reacts with benzidine to turn it blue

How to test to see if a potential bloodstain is actually blood?

kastle-meyer color test

the breakdown of peroxides by hemoglobin; turns pink and proves blood has been found

Leucomalachite

it is oxidized by hemoglobin, making the test strip turn green which means positive for blood

Takayama and Teichmann

adding a solution of potassium forming crystals with hemoglobin; observed under microscope to see if blood is found

Precipitin test

uses animal serum containing antibodies causing human blood to clump

serum

a liquid that separates from clotted blood

the red blood cells have ruptured but the antigens and anitbodies are still presents

why can real blood that is dried up still be typed

use paper bags to allow air to access the blood stain

how do investigators collect blood

the patterns left by falling, projected, or smeared blood

what can help a forensic investigator interpret and reconstruct what happened at a crime scene?

to prove or disprove the suspect's account of what happened

what are blood spatter patterns often used for?

direction of travel, angle of impact, number of blows, lefty or righty

what can blood spatter reveal?

spatter

bloodstains created from the applying force to the area where blood originated

angle of impact

the angle at which a blood droplet strikes a surface

parent drop

the droplet from which the satelitte spatter originates

satelitte spatter

small drops of blood that break from the parent drop when the blood droplet hits a surface

spines

the pointed edges of a stain that radiate out from spatter and can determine the direction the blood traveled in

void

area in a blood spatter crime scene where no spatter is found; can tell height, location of attacker, etc.)

passive bloodstains

patterns created from the force of gravity

projected bloodstains

occur when a force is applied to the source of the blood

transfer or contact bloodstains

created when a wet, bloody object comes in contact with a target surface

swipe and wipe pattern

Two types of transfer bloodstains?

wipe pattern

object moving through a bloodstain

swipe pattern

object leaving a bloodstain